Conversion Rate, Cardholder Billing
What it is
Rate converting DE 4 into the cardholder billing amount (DE 6). First digit is the decimal-shift exponent.
Example values
61234567Rate 1.234567 (leading 6 shifts the decimal six places).DE 10 on the wire
Bitmap position
DE 10 is bit 10 of the primary bitmap: byte 2, mask 0x40. A primary bitmap with only DE 10 present reads 0040000000000000 in hex.
Length
DE 10 is fixed length: always 8 digits, with no length prefix. A parser reads exactly that many and moves on, so shorter values are right-aligned and padded with leading zeros.
Size in the message
At most 8 bytes when the message travels as text (ASCII or EBCDIC), or 4 bytes in binary dialects that pack digits as BCD.
Format n
Format n means numeric: the digits 0–9 only.
Specification reference
Defined in ISO 8583:1987 (base). Card networks publish their own dialect tables (Visa BASE I / V.I.P., Mastercard CIS) that refine formats, lengths, and — for private-use elements — the entire layout. Always confirm against the interface specification you implement.